i fe) The Natural Hiftory of the Book 1 
But, without laying any Strefs upon: the above Inftances, it will not bg 
very difficult to explain, in fome meafure, the Reafon of fo vifiblea con: 
ftitutional Difference in the Inhabitants of hot and cold Climates. : 
‘The confi. As (t3) Heat in the former rarefies and increafes the Velocity of the 
fitional Dif’ Fluids, confequently the Particles of Blood, thus expanded, meeting in 
the Inhabit- their Circulation (even in the iminuteft Veffels) no Obftacle from the 
andcod external Preffure of Cold, nor any Languidnels by immoderate Heat, it 
Climates follows, that as Health confifts in an equal Motion of the Fluids, and Re- 
examined in 
anew and ‘fiftance of the Solids, fuch an even Temperament of the Air muft 
et “be more friendly to, and productive of, Health and Chearfulnefs, than in 
Climates where often, by fevere cold Weather, the Globules of Blood 
lofe in a great meafure their Motion, efpecially towards the Extremities 
of the Body, where at fuch times they cohere in Mafies too large to pats 
freely through the minute capillary Veffels. When this Harmony be- 
tween the Solids and Fluids is difconcerted, then arifes, as Experience 
teaches us, a fudden Senfe of Pain, which cannot be removed till the 
Blood is, as it were, thawed by Heat, and fo recovers its uninterrupted 
Motion : And tho’ we know not certainly how to define what the Ani- 
mal Spirits are ; yet, on Suppofition that they are the moft refined and 
ative Particles of the Blood, as they are with great Reafon thought to : 
be, their pleafing, or painful, Influence on the Body muft, in a great 
meafure, depend upon the regular or irregular Motion of their original 
conftituent Fluid, the Blood : -Now, when this is checked in its Circula- 
tion, either by a fudden Preffure of an heavy Atmofphere, or the Varia- 
blenefs of the Winds from warm to cold; the Animal Spirits, which be- 
fore were agreeably diffufed through the whole Body, by thefe fadden 
{nterruptions in the Blood, their original Source, likewife become un- 
able to perform ‘their Functions:; for, when Nature is impeded in any of 
her Operations neceflary to our Well-being, whether natural, vital; or 
animal, that mutual and infeparable Connexion. between the Mind and 
the Body will appear fo vifibly, that if the latter be affe@ed with Pain, — 
the neceflary Confequence of ObftruGions in the Fluids, the former foon 
lofes that Chearfulnefs which is naturally lefs interrupted, and may be 
_ better preferved, in Climates obnoxious to no fudden Viciflitudes of Wea. 
ther, from moift to dry, from hot to cold; for an even Temperature of 
the Air is‘beft adapted to fupport the (14) Body in that State which is 
requifite - 
‘This, in general, may be true, efpecially of thofe who are daily expofed to hard Labour, and confequently 
fweat much : But, with regard to the white Inhabitants of this Mand, this fuppofed eigtiey is not fo great ; 
i iluters of every 
; ; f equal Degree of Heat 
Cold, in a clofe Room, and a warm Bed ? However, it muft’ be owned, that fotalee Chindtcs So piss 
Inconveniencies ; they are yery improper for thofe Conftitutions which Tequire much bodily Exercife 3 for 
it 
